Garmin GPSMAP Tide data

[FulmarJeddo]

I went to the show on Wednesday and came back with a Garmin GPSMAP 550. I connected it up to a battery at home and had a bit of a play. One of its functions is to display tide data. I don't have a current almanac at the moment but compared the tide times at London Bridge with a tide table I have and found about a 30 min difference. I also checked it against easy tide which was a few minutes difference to my tide table. I haven't checked it against other locations yet but so far it doesn't appear very accurate. Has anyone any experience of Garmin's tide data?
Incidentally, anyone still to go to the show I got a very good deal from Redcar Electronics and they were extremely helpful. It was the first stand I went to and no one would better their prices. £389 for the plotter and £125 for a Standard Horizon GX1500E DSC radio with a Remote Access Mike. With a bit of haggling even got a bit more shaved off the price.

 

[CaptainBob]

I've found slight differences between Reeds and my Garmin. Not sure about 30 mins though. On mine, I have other weird issues - I select the date I want tides for, and then it shows me the tide, then randomly changes the date display... doesn't instill confidence really. I'm going to use it as a double-check only.